Selenium is a powerful suite of tools designed for automating web browsers. Initially developed for testing web applications, it has evolved into a versatile framework that can be used for various tasks, including web scraping and automating repetitive web-based activities. Selenium supports multiple programming languages, such as Python, Java, and C#, allowing developers to write scripts that interact with web elements like buttons, text boxes, and links. Its flexibility enables users to run tests on local machines or in the cloud, making it a popular choice among developers and testers alike for ensuring web application functionality and performance.